Alternating-current electromagnet.



j a 4' v 0.1. LINDQUIST. v ALTERNATING CURRENT ELECTROMAGNET. APPLICATION FILED FEB- 6, 1913- RENEWED NOV. 9,19l5-' 15186:) 1 4 Patented J 11116 6, 1916.

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I To all whom it may concern.

1 "UNITED STATES PATENT or w DAVID L. LmnoUIs'r, or YONKERS, NEW YORK, assrsnoa T0 OTIS ELEVATOR COM- PAN'Y, or NEW YORK, N. Y., A CORPORATION or NEW JERSEY.

ALTERNATING-QURREN T ELECTROMAGNET.

Specification of Letters Patent.

Patented J line 6, 1916.

Application filed February 6; 1913, Serial No. 746,445. Renewed November 9, 1915. Serial No. 60,530.

Be it known that I, DAVID L. LINDQUIST, a subject of the King of Sweden, residing at Yonkers, in the county of Westchester and State of New York, have invented a certain new and useful Improvement in Alternating-Current Electromagnets, of which the following is a specification.

The invention relates to an alternating current electroimagnet, of the general type disclosed in U. S. Letters Patent No.744,773,

granted to me November 24, 1903, and more particularly to the specific type dlsclosed in U. S. Letters Patent No. 1,005,855, granted to me October 17th, 1911, wherein the core carries secondary conductors, in which is induced a current different in hase from that energizing the primary coll. A's set forth in the aforesaid Letters Patent, such an alternating current magnet will hold its moving core member firmly in attracted position without vibration or chattering.

My present invention consists in the secondary conductor, or conductors, made in the form of a straight bar or rod disposed transversely across and preferably through the laminated core. The secondary current then circulates within the mass of said bar, as hereinafter explained.

In the accompanying drawings- Figure 1 is a longitudinal section of an alternating current electro-magnet embodying my pres-' ent invention.

Figs. 2 and 3 are similar views of modified forms thereof. Fig. l is a vertical section on the line a", w of Fig. 1. Fig. 5 is a similar section on the line y, y of Fig. 3. Fig. 6 shows diagrammatically the current path in bar F, viewed in plan.

Similar letters of reference indicate like parts.

A is the primary coil, inclosed in a castwo parts C and D. The part C isclamped in the casing by the set screw E, and the part D is movable in the coil,and constitutes the armature.

In the form shown in Fig. 1, a straight bar or cylinder F of magnetic material is secure transversely across the core laminations, and preferably passes through them.

Said bar may serve as a rivet to hold thelaminations together. a

When single-phase alternating current is supplied to the coil A, a current of different phase is induced in the bar F, and circulates- L conductors each furnishin 'at right angles to the core laminations, this mode of excitation being the well'kn'own split-phase inductive method. As already fully explained in my previous patents, under these conditions the current energizing the magnet never falls to zero, and by reason of the magnetic symmetry, a constant resultant pull in a straight line coincident with the axis of symmetry of the magnet is exerted upon the armature D to hold it firmly attracted, without chattering or vibration. The bar F may be a part of the stationary portion .C of the core, or of the movable portion D, or ofeach portion C and D, as shown in Fig 2. Instead of using but one bar F, as "shown in Fig. 1, I may employ a plurality of bars F, G, as shown in Fig. 3. Where one of said bars, as G, is placed farther away from the pole than the other bar, F, it will produce a less magnetic effect.

coil, a laminated core, and a conductor. fur- 35 nishing a closed secondary circuit in the form of a straight bar of magnetic material extending transversely across the laminations of said core and having its end pieces terminating in proximity to opposite surfaces thereof.

2. Analternatirig current electro-magnet of the type set forth, comprising a primary coil, a laminated core, and a conductor furnishing a closed secondary circuit in the form of a bar of magnetic material extending B- The laminated core is formed in ing transversely across and through the laminations of said core.

3. An alternating currentelectro magnet of the type set forth, comprising a primary coil, a laminated core, and a plurality of conductors each furnishin a closed secondary circuit in the form 0 separate bars of magnetic material extending transversely across the laminations of said core.

1 4. An alternatin current electro-magnet of the type set fort comprising a primary coil, a laminated core, and a plurality of a closed secondary circuit in the form 0 separatebars of no magnetic material extending transversely and through the laminations thereof and across the lamlnations of said core and (11S- formmg a secondary to said primary coll. 1O

posed at different distances from a polar In testimony whereof I have afiixed my extremity thereof. signature in presence of two witnesses.

5. An alternating current electro-magnet DAVID L. LINDQUIST. of the type set forth, comprising a primary Witnesses: coil, a laminated core, and a rivet of mag- GERTRUDE T. PORTER, netic material extending transversely across MAY T. MoGARRr.

Copies of thie potent my be obtained for five cents each, by addressing the "Commissioner at retail,

. Wuhington, D. G." 

